Master cylinder



FIG. 1 is a perspective view of the design;

FIG. 2 is a side view of the design, the opposite side being a mirror image;

FIG. 3 is a top view of FIG. 1;

FIG. 4 is a bottom view of FIG. 1;

FIG. 5 is a front elevational view of FIG. 1; and,

FIG. 6 is a rear elevational view of FIG. 1.

The broken lines showing portions of the master cylinder and associated elements form no part of the claimed design. 

The ornamental design for a master cylinder, as shown and described. 